Addiction-like symptoms in relation to excessive and compulsive social media use are common in the general population. Because they can lead to various adverse effects, there is a growing need to understand the brain systems and processes that are involved in potential social media addiction. We focus on the morphology of the posterior subdivision of the insular cortex (i.e., the insula), because it has been shown to be instrumental to supporting the maintenance of substance addictions and problematic behaviors. Assuming that social media addiction shares neural similarities with more established ones and consistent with evidence from the neuroeconomics domain, we further examine one possible reason for this association—namely that insular morphology influences one's delay discounting and that this delay discounting contributes to exaggerated preference for immediate social media rewards and consequent addiction-like symptoms. Based on voxel-based morphometry techniques applied to MRI scans of 32 social media users, we show that the gray matter volumes of the bilateral posterior insula are negatively associated with social media addiction symptoms. We further show that this association is mediated by delay discounting. This provides initial evidence that insular morphology can be associated with potential social media addiction, in part, through its contribution to poor foresight and impulsivity as captured by delay discounting. 相似文献
Several eye-movement studies have revealed flexibility in the parafoveal processing of character-order information in Chinese reading. In particular, studies show that processing a two-character word in a sentence benefits more from parafoveal preview of a nonword created by transposing rather than replacing its two characters. One issue that has not been investigated is whether the contextual predictability of the target word influences this processing of character order information. However, such a finding would provide novel evidence for an early influence of context on lexical processing in Chinese reading. Accordingly, we investigated this issue in an eye-movement experiment using the boundary paradigm and sentences containing two-character target words with high or low contextual predictability. Prior to the reader’s gaze crossing an invisible boundary, each target word was shown normally (i.e. a valid preview) or with its two characters either transposed or replaced by unrelated characters to create invalid nonword previews. These invalid previews reverted to the target word once the reader’s gaze crossed the invisible boundary. The results showed larger preview benefits (i.e. a decrease in fixation times) for target words following transposed-character than substituted-character previews, revealing a transposed-character effect similar to that in previous research. In addition, a word predictability effect (shorter fixation times for words with high than low predictability) was observed following both valid and transposed-character previews, but not substituted-character previews. The findings therefore reveal that context can influence an early stage of lexical processing in Chinese reading during which character order is processed flexibly.
